In a world where mothers are obligated to take their son's virginity in sex education, mothers are only allowed to lose their virginity once!

In a world where mothers are obligated to take their son's virginity in sex education, mothers are only allowed to lose their virginity once! They were only supposed to teach him the correct sexual knowledge, but... she got hooked on her son's dick, which is more energetic than her husband's, and fell into the pleasure of forbidden mother-son incest!!